The Superconductive Circuit Board

If you work with printed circuit boards or the PCBA industry, then you have probably heard of immersion white tin, but may have questions about how it actually works and whether it's a process that you should care about.

Given that we are leaders in immersion white tin PCB fabrication here at Omni, it goes without saying that we are heavily in favor of its use. To understand why, you first have to understand the reason behind our preference for white tin in the first place. Traditionally, circuit boards have been finished with a coating of material, usually containing lead, as part of the soldering process. That's great for the functionality of printed circuit boards, but less friendly for the environment since these metals (and the byproducts created) can be extremely toxic.

One of the more interesting activities routinely associated with PCB manufacturing is the process of assembling multilayer circuit boards.

At any given time 40% of our PCB manufacturing at Omni is producing multilayer circuit boards, so understanding the process is important. Layers of copper foil, prepreg and core material are sandwiched together under high temperature and pressure to produce multilayer assemblies. Pressure is needed to squeeze out air while heat is required to melt and cure the thermosetting “prepreg” adhesive which holds the multilayer PCB together.

Mention Immersion White Tin around sales people from PCB shops and Tin Whiskers will inevitably be part of the topic.

They may not feel comfortable down mouthing the competition in public but a process? Well that’s fair game. What the salespeople don’t know or won’t tell you is the Immersion Tin used as a finish for circuit boards completely dissolves in the solder used in the circuit board assembly process.